LED Chip Research Articles

Size-dependent competitive effect between surface recombination and self-heat on efficiency droop for 250 nm AlGaN-based DUV LEDs.

In this work, electrical and optical performances for 250 nm AlGaN-based flip-chip deep ultraviolet light emitting diodes (DUV LEDs) with different chip sizes are studied. Reduced chip size helps increase the light extraction efficiency (LEE) with the cost of increased surface nonradiative recombination. Nevertheless, a thin p-Al0.67-0Ga0.33-1N layer of 10 nm can manage current distribution while suppressing surface recombination and reducing light absorption simultaneously, which results in the increased optical power density. Thanks to the better current management and reduced optical self-absorption effect, the reduced Joule heating effect suppresses the thermal droop of the optical power density for a small DUV LED chip. We also find that the p-Al0.67-0Ga0.33-1N layer thickness shows very significant impact on device resistance especially for the small DUV LED chip, such that the device resistance has a remarkable increase when the p-Al0.67-0Ga0.33-1N layer is thickened to 100 nm.

A well-performed green-emitting Lu1.5Ca1.5Al3.5Si1.5O12:Ce3+ garnet phosphor for high-quality pc-WLEDs

High-brightness and thermally-stable broadband green-emitting phosphors are highly demanded for the fabrication of high-quality phosphor-converted white light-emitting diodes (pc-WLEDs) with high color rendering index (CRI) and low correlated color temperature (CCT). Herein, we report on the synthesis, luminescent properties, thermal stability and application of a novel highly efficient green-emitting Lu1.5Ca1.5Al3.5Si1.5O12:Ce3+ garnet-type phosphor for blue-chip-pumped high-CRI pc-WLEDs. A series of Lu1.5Ca1.5Al3.5Si1.5O12:Ce3+ green phosphors doped with various Ce3+ concentrations (0.5-4 mol%) have been prepared by a conventional high-temperature solid-state reaction approach. Impressively, the composition-optimized Lu1.5Ca1.5Al3.5Si1.5O12:2%Ce3+ sample exhibits a broad excitation band in the 400-500 nm spectral range with an excitation peak around 451 nm, and it gives rise to a bright broad green emission band in the 470-700 nm wavelength region (emission peak: 533 nm; bandwidth: 108 nm) with CIE color coordinates of (0.3361, 0.5640). Notably, high luminescence efficiency is obtained for Lu1.5Ca1.5Al3.5Si1.5O12:2%Ce3+ phosphor (internal quantum efficiency: 92.2%; external quantum efficiency: 50.7%). Moreover, it is also found that Lu1.5Ca1.5Al3.5Si1.5O12:2%Ce3+ shows excellent resistance to thermal quenching, while its emission intensity at 423 K remains 76% of the initial value at room temperature. Amazingly, the color stability of Lu1.5Ca1.5Al3.5Si1.5O12:2%Ce3+ is also outstanding, and only a very small chromaticity shift (3.99 × 10−3) is observed at 423 K. A high-performance pc-WLED device has been fabricated by using a 450 nm blue-emitting LED chip and as-prepared Lu1.5Ca1.5Al3.5Si1.5O12:2%Ce3+ green phosphor as well as commercial CaAlSiN3:Eu2+ red phosphor. Such device produces a bright warm-white emission under 280 mA driving current, demonstrating super CIE chromaticity coordinates (0.3870, 0.3818), high CRI of 93.8, low CCT of 3865 K, and high luminous efficacy (51.86 lmW-1).

Photodamage prediction model and optimal lighting system for polychrome artworks in museum

When lighting polychrome artworks in museum, the light sources are required not only to provide high-quality visual performance, but also to minimize the photodamage. Currently, though there are mature methods to calculate visual performance, how to predict the degree of photodamage remains a challenge, which leads to a lack of light sources satisfying both visual and protection requirements. Our study conducted a series of 294 accelerated aging experiments spanning over 11 years for materials commonly used in Chinese polychrome artworks, using isoenergetic white-light D55 and 10 different wavelengths of narrow-band light as experimental light sources. The mathematical model predicting the photodamage degree caused by intensity (I), exposure time (t), the relative spectral power distribution of the light source (S(λ)), and the irradiated material's relative spectral responsivity (P(λ)) to polychrome artworks was established, and the mean absolute percentage error of the model, as verified by experiments, was 11.63 %. Combined with the existing visual performance calculation methods, an optimal lighting algorithm that simultaneously meets high-quality visual performance and minimum photodamage was developed, followed by developing a new Spectrally Tunable White LEDs (STWLEDs) lighting system with 10 LED chips. It is found that the STWLEDs can adjust and output the optimal spectra and recommended illuminance according to the characteristics of polychrome artworks, thus realizing lighting with minimum photodamage, meanwhile, satisfying high-quality visual performance. After testing, as well as satisfying the requirements of visual performance, the average photodamage is reduced by 40.95 % with STWLEDs compared with the traditional WLEDs.

Self-assembled nest-like BN skeletons enable polymer composites with high thermal management capacity

The lagging development of thermally conductive but electrically insulating materials has become a bottleneck problem for the next generation of advanced high-power density electronic devices. Although second-phase reinforced composites are promising materials for addressing thermal management issues, the inherent mechanism of severe phonon scattering at the interphase results in actual thermal conductivity enhancement efficiency far below expectations. Here, we report a high-performance polymer composite with a nest-like interconnected boron nitride skeleton. This nest-like interconnected BN skeleton without mechanical contact can provide high-efficiency and long-distance phonon transport channel, realizing high thermal conductivity of 1.827 W m-1 K-1 in polymer composite with ultra-low content (4.7 vol%). Meanwhile, the EP/ nest-like BS composites possess ideal electrical properties and dimensional stability. In the actual heat dissipation process of LED chips, the optimal composite material as the thermal interface material can display a temperature drop of more than 34.8% compared to neat epoxy, which proves the broad application prospects of this strategy in advanced electronic devices.

Structure-Photoluminescence Relationship in Ce3+-Doped K5Y(P2O7)2 and Its Sensitization to Dy3+ with Enhanced White Light Emission.

From a fundamental point of view, the structure-photoluminescence relationship is vitally important for developing efficient phosphors and rationally improving their performances. In this work, Rietveld refinements on high-resolution powder X-ray diffraction (XRD) data were conducted to verify the Ce3+ distribution in K5Y(P2O7)2 (KYPO). Ce3+ ions are located at both M1 and M2 sites, with occupation factors of 0.31(2) and 0.19(2), respectively. Importantly, the crystal field strength (CFS) is stronger at the former site due to the larger bond valence sum. Correspondingly, the Ce3+ emission can be deconvoluted into four Gaussian-type bands centered at ∼353, ∼383, ∼343, and ∼369 nm, where the former two belong to Ce3+ at the M1 site and the latter two are assigned to Ce3+ at the M2 site. Ce3+ in KYPO is a highly efficient activator, with optimal internal and external quantum efficiencies of 98.9 and 74.6%, respectively, and was thus utilized to sensitize the Dy3+ emission. Indeed, energy transfer from Ce3+ to Dy3+ was confirmed by fluorescent decay curves for Ce3+/Dy3+ codoped KYPO, and the mechanism was supposed to be dominated by dipole-dipole interactions. Indeed, it can be pumped by a 310 nm LED chip and emits a bright white light. Ce3+ photoluminescence exhibits high resistance to thermal quenching, and it can be further enhanced by codoping Dy3+, i.e. the emission intensity remains 96.3% at 423 K.

Cr3+-Doped LiAlO2 NIR-I Emitting Phosphors with Superior Resistance to Thermal Quenching for Night Vision Monitoring and Bioimaging.

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) as a new NIR light source has outstanding application potential in the fields of NIR spectroscopy analysis, sensing, imaging, and pattern recognition. Therefore, the development of NIR phosphors with good NIR luminescence thermal stability has attracted much attention. To this end, we developed LiAlO2:Cr3+ garnet-type NIR phosphors by a high-temperature solid-state reaction method. Under 405 nm excitation, the Cr3+ ions located in tetrahedrons of LiAlO2 emit NIR emission in a broadband NIR emission that covers 650-900 nm mixed with several sharp narrowband R-line emissions, which showed excellent luminescence thermal stability with integrated intensity of emission measured at 573 K is ∼90.86% of that measured at 303 K caused by good structural rigidity and low thermal expansion coefficient of the matrix material. An NIR pc-LED device assembled with the optimized LiAlO2:Cr3+ and a commercially available purple LED chip emitted NIR output power of ∼98.172 mW at a driving current of 300 mA and demonstrated an electro-optical conversion efficiency of ∼9.09%, while demonstrated it has excellent application potential in the fields of night vision monitoring and biomedical imaging.

Novel narrowband emitting red phosphor Sr3La2W2O12:Eu3+ with excellent thermal stability for WLEDs

AbstractThe development of red phosphors with good thermal stability, high quantum yield and high color purity is still a big challenge. In this work, a series of novel red phosphors Sr3La2W2O12:xEu3+ (0≤x≤0.18, ∆x = 0.03) were successfully prepared by high‐temperature solid‐phase method. The phosphors reveal a hexagonal phase with the space group of R‐3 m. The phosphor Sr3La2W2O12:Eu3+ produced narrowband red emission from 5D0→7F2 of Eu3+ (616 nm) under excitation at 395 nm, 465 nm, and 533 nm. Importantly, phosphor Sr3La2W2O12:0.09Eu3+ exhibits astonishing quantum efficiency (IQE = 89.60%, EQE = 41.52%), and it demonstrate robust thermal performance with the emission intensity retaining 92.73% at 558 K of that at 298 K. Finally, the prepared red phosphor Sr3La2W2O12:0.09Eu3+ and yellow phosphor YAG:Ce3+ were combined with a blue LED chip (460 nm) to form a WLED device, which presented warm white light with color coordinates of (0.3523, 0.3732), color rendering index of 83.7, and color temperature of 4826 K.

Full-Visible-Spectrum White LEDs Enabled by a Blue-Light-Excitable Cyan Phosphor.

Efficient blue-light-excitable broadband cyan-emitting phosphors may yield full-visible-spectrum white light-emitting diodes (WLEDs) with ultrahigh color rendering (Ra > 95). However, this requires closing the "cyan gap" in the 480-520 nm region of the visible spectrum, which is challenging. Herein, a well-performed cyan-emitting garnet phosphor Ca2LuAlGa2Si2O12:Ce3+ (CLAGSO:Ce3+) is reported. Under 430 nm excitation, the optimal CLAGSO:5%Ce3+ compound exhibits a broadband cyan emission (peak, 496 nm; bandwidth, 102 nm) with a high internal quantum efficiency of 85.6% and an excellent thermal resistance performance (69.1% at 423 K). Importantly, this as-prepared cyan-emitting phosphor provides sufficient cyan emission and enables filling the well-known so-called "cyan gap" between the blue LED chip and the commercial Y3Al5O12:Ce3+ (YAG:Ce3+) yellow phosphor. Impressively, a WLED device fabricated with the optimal CLAGSO:5%Ce3+ sample shows a low correlated color temperature (4053 K) and an ultrahigh color rendering index (Ra = 96.6), as well as an excellent luminous efficacy (74.09 lm W-1). These results highlight the importance of blue-excited broadband cyan-emitting phosphors in closing the cyan gap and enabling human-centric full-visible-spectrum warm WLED devices for high-quality solid-state lighting.

Enhancing optical output power efficiency in nitride‐based green micro light‐emitting diodes by sidewall ion implantation

AbstractThough micro‐LED (light‐emitting diode) displays are considered the emerging display technology, the micron‐scale LED chip size encounters severe efficiency degradation that may impact the power budget of the displays. This work proposes an ion implantation method to deliberately create a high‐resistivity sidewall in the InGaN/GaN green LED. Our study demonstrates that ion implantation suppresses reverse leakage current due to the mitigation of sidewall defects. For an LED mesa size of 10 × 10 μm2, optical output power density is improved by 36.2% compared to the device without implantation. Compared to a larger 100 × 100 μm2 device without implantation, we achieve only 21.3% degradation of output power density under 10 A/cm2 injection for a 10 × 10 μm2 LED with implantation. In addition, the ion implantation method can lower the wavelength shift by reducing light emission from the region near the sidewall (where the amount of Indium [In] clustering differs from the mesa region). The results show promise in addressing the efficiency challenges of micro‐LED displays by selective ion implantation.

Tuneable Red and Blue Emission of Bi3+-Co-Doped SrF2:Eu3+ Nanophosphors for LEDs in Agricultural Applications.

Tunable blue/red dual-emitting Eu3+-doped, Bi3+-sensitized SrF2 phosphors were synthesized utilizing a solvothermal-microwave method. All phosphors have cubic structure (Fm-3m (225) space group) and well-distinct sphere-like particles with a size of ~20 nm, as examined by X-ray diffraction and transmission electron microscopy. The diffuse reflectance spectra reveal a redshift of the absorption band in the UV region as the Bi3+ concentration in SrF2: Eu3+ phosphor increases. Under the 265 nm excitation, photoluminescence spectra show emission at around 400 nm from the host matrix and characteristic orange 5D0 → 7F1,2 and deep red 5D0 → 7F4 Eu3+ emissions. The red emission intensity increases with an increase in Bi3+ concentration up to 20 mol%, after which it decreases. The integrated intensity of Eu3+ red emission in the representative 20 mol% Bi3+ co-doped SrF2:10 mol% Eu3+ shows twice as bright emission compared to the Bi3+-free sample. To demonstrate the potential application in LEDs for artificial light-based plant factories, the powder with the highest emission intensity, SrF2: 10Eu, 20 Bi, was mixed with a ceramic binder and placed on top of a 275 nm UVC LED chip, showing pinkish violet light corresponding to blue (409 nm) and red (592, 614, and 700 nm) phosphors' emission.

Preparation of Imidazole Compounds as Latent Curing Agents and Their Application in RGB LED Packaging.

LED packaging miniaturization has raised more requirements for LED materials. As a material contacting the LED chip directly, the reliability of LED non-conductive adhesive has also garnered increasing attention. This study optimized the formula for non-conductive adhesives for an imidazole curing system. The optimized composition of the adhesive is 25%wt for the curing agent and 30%wt for the silica. The prepared non-conductive adhesive has a 7-day pot life and 9-month storage stability. The shear strength reached 87 g and 72 g at 25 °C and 160 °C, respectively. The reliability of the LED modules packaged with the non-conductive adhesive was researched. The green and blue light intensity change was 4.7%, 43.7%, respectively, indicating good anti-aging properties. The blue light decay was mainly due to adhesive aging. The non-conductive adhesive effectively prevented "caterpillar" growth. This provides useful and practical guidelines for industry for applications of adhesive in different packages.

Insight into Structure, Regulatable Photoluminescence of Stably Self and Codoped Phosphor Ba3Y2B6O15: Dy/Eu for nUV wLEDs

AbstractThe exploitation of borate‐based phosphors is garnered tremendous attention in wLEDs. Although previous research provided some insights into borates from the viewpoints of synthesis, structure, and defect evolutions, their photoluminescence (PL) with dopants is still insufficient for actual application, especially on aspects of efficiency/stability. Herein, to alleviate the above issues, a new type of lesser‐known high symmetry Ba3Y2B6O15 (BYB) codoped with Dy3+/Eu3+ phosphors are synthesized via multistep solid‐state reaction and possessed controllable PL based on nUV excitation, defect‐induced (self‐) PL, and energy transfer (ET) from Dy3+ to Eu3+. The origin of blue self‐PL is clarified based on oxygen‐related defects and optimized via adjusting synthetic atmosphere (air/Ar) and (co)doping dopants to control the defect content. Thanks to dense connectivity, and highly symmetric structure with perfectly ordered octahedral sites of Y3+ for accommodation of Dy/Eu and ET, “cool” white and red PL from Dy3+ and Eu3+, respectively, show high PL efficiency with narrow full width at half the maximum (fwhm). The phosphor also exhibits excellent thermal stability because of high bandgap and low electron‐phonon coupling. Finally, a high‐quality phosphor‐converted wLED (pc‐wLED) device is assembled via remote “capping” packaging by adopting the BYB: Dy/Eu and a 350 nm nUV LED chip.

Photoluminescence properties of Mn2+-activated red-emitting phosphors with superior thermal stability for backlighting display applications

The red-emitting phosphors, Na2Mg1-x(PO3)4:xMn2+ with concentrations ranging from 0.01 to 0.11, have been successfully synthesized using a simple solid-state method. The as-synthesized phosphors are crystallized in an orthorhombic structure. The luminescence mechanism of Mn2+ ions in Na2Mg(PO3)4 lattice has been deeply explained using the Tanabe-Sugano (T-S) energy level diagram for the d5 electron configuration. The typical photoluminescent emission (PL) and photoluminescent excitation (PLE) spectra were measured. Several excitation peaks in the spectral range of 250–550 nm on the PLE spectrum and a strong emission peak at 613 nm indicate that the as-synthesized phosphors can be effectively excited using ultraviolet (UV) and near-UV LED chips. Several photometric characteristics were measured, such as the Commission International de'LEclarirage (CIE) chromaticity coordinate (x, y), color purity (CP), and correlated color temperature (CCT), corresponding to the concentration-dependent PL spectra. Furthermore, the thermal stability of the Na2Mg1-x(PO3)4:xMn2+ phosphors was investigated through temperature-dependent PL spectra and decay curves from 10 to 500 K. All results confirm that the as-synthesized red-emitting phosphors exhibit excellent thermal stability, which are attractive characteristics for white light emitting diodes (W-LEDs) applications.

Structure development and photoluminescence properties of high-purity greenish-yellow emitting LaGaO3:Dy3+ phosphors

This study investigates the structure development and photoluminescence properties of high-purity greenish-yellow emitting LaGaO3 phosphors doped with dysprosium ions Dy3+. The phosphors were synthesized using a high-temperature solid-state reaction method. X-ray diffraction (XRD) confirmed the formation of a single-phase LaGaO3:Dy3+ structure and scanning electron microscopy (SEM) revealed uniform particle size and morphology. The phosphor exhibits the capability of being efficiently excited by ultraviolet 350 nm exhibiting the characteristic greenish-yellow emission with two strong peaks at 478 nm (cyan) and 572 nm (yellow), ascribing to the transitions of 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2, respectively. The electronic transition mechanism is direct exchange interaction between activators, contributing to the concentration quenching. The phosphor was able to retain 67 % of its intensity without significant color change at an elevated temperature up to 25 °C to 150 °C. The CIE chromaticity coordinates of the emitted light were calculated and found in the desired greenish-yellow region. The electroluminescence performance of the LaGaO3:0.06Dy3+ phosphor was investigated using 365 nm LED chips to check their applicability in the field of white light-emitting diodes (WLEDs). The synthesized phosphors demonstrated high thermal stability, making them suitable for white-LED applications. The study highlights the potential of LaGaO3:Dy3+ phosphors in enhancing white-LEDs' color quality and efficiency.

Low-temperature attaching of LED chips using SnBiIn solder nanoparticles

Low-temperature attaching of LED chips using SnBiIn solder nanoparticles

Crystal structure and spectral tuning of Eu2+/Eu3+ co-activated Na2Ba1-xSrxCa(PO4)2 phosphors with high thermal stability

The coupling of UV LED chips with phosphors to produce white or color-tunable light is still a challenge. In this work, we propose a simple rare earth occupation site engineering method to adjust the valence of doped Eu ions. Based on the Ba2+ substituted by Sr2+, new Eu2+/Eu3+ co-activated Na2Ba1-xSrxCa(PO4)2 (NB1-xSxCP) phosphors were designed and successfully synthesized. In NB1-xSxCP, the Ba2+/Sr2+ site is occupied by Eu2+, while the Ca2+ site is occupied by Eu3+. The coupled broad blue 448 nm and sharp red 619 nm luminescence under 321 nm excitation has demonstrated the coexistence of Eu2+ and Eu3+. This double emission phenomenon is studied in terms of the fluorescence lifetime as well as lattice distortion induced by the substitution ions. With the increased substitution of Sr, the luminescence of NB1-xSxCP:0.03Eu2+/3+ can be tuned from blue to red crossing the warm-white region. When x = 0.3, the chromaticity coordinates is located at (0.3779, 0.2495). The integrated intensity of Na2Ba0.7Sr0.3Ca(PO4)2:0.03Eu2+/3+ at 150℃ remains 90.9 % of that at room temperature, while the chromaticity shift (ΔE) can be calculated as 15 ×10−3. The Eu2+/Eu3+ co-activated NB1-xSxCP is a potential candidate for single-phase color-tunable phosphors used for light-tunable applications due to the combining contributions from both Eu3+ and Eu2+ ions.

An LED light propagation cavity with staggered light bars for eliminating the Hot Spot

The light source of traditional edge-lit backlight modules typically consists of LED bars which composed of multiple LED chips. However, the spacing between the chips can create distinct bright and dark spots (Hot Spot) on the input surface of the light guide plate (LGP), thereby affecting the optical performance of the backlight module. In this paper, we proposed an edge-lit backlight module with staggered light bars, incorporating a light propagation cavity design to enhance light receiving efficiency and eliminate Hot Spot. Firstly, we designed the structure of the staggered light bars and the light propagation cavity. Secondly, the advantages of the new backlight module design in eliminating Hot Spot were verified through TracePro simulations. The simulation results showed that the maximum irradiance of the backlight module reached 81,010 W/m2, and the luminance uniformity peaked at 75.142 %. Compared to the traditional backlight modules, the light receiving efficiency was increased by 6.62 %, and the luminance uniformity was improved by 1.34 times, which effectively mitigated the Hot Spot. Finally, we discussed the impact of the improved backlight module in reducing the thickness of the LGP and decreasing the number of LED chips, achieved superior optical performance. This study demonstrates the significant advantages of the light propagation cavity in eliminating Hot Spot within backlight modules.

Designing a high-efficiency broadband cyan phosphor for low-blue full-spectrum LED lighting

Efficient cyan-emitting phosphor plays an important role in the development of solid-state lighting, which is indispensable to filling the cyan gap for full-spectrum warm-white light-emitting diodes (WLEDs) with high color rendering index (CRI). Herein, a novel highly efficient broadband cyan phosphor Ce3+-doped Ca3HfAl2Si2O12 (CHASO: Ce3+) garnet compound was developed by the substitution of Lu3+-Al3+ with Ca2+-Hf4+/Si4+ in Lu3Al5O12. The crystal structure and photoluminescence (PL) properties of CHASO: Ce3+ were investigated in detail. Notably, CHASO: Ce3+ phosphor can be effectively excited by violet light (390 – 430 nm) and exhibited bright cyan emissions around 490 nm with high PL internal quantum yields of 89.2 %. Moreover, the integrated PL intensity of the phosphor at 423 K was 66.3 % of that at room temperature. Finally, by incorporating CHASO: 11 %Ce3+ with commercial blue/yellow/red phosphor onto a violet LED chip (400 nm), the prototype full-spectrum WLEDs device exhibits warm white light with high color rendering index (CRI, Ra and R9 > 90) and low correlated color temperature 3301 K. These results suggest the highly efficient phosphor CHASO: Ce3+ is promising for low-blue full-spectrum healthy lighting.

Constructing the Snail Shell-Like Framework in Thermal Interface Materials for Enhanced Through-Plane Thermal Conductivity.

Melioration of the through-plane thermal conductivity (TC) of thermal interface materials (TIMs) is a sore need for efficient heat dissipation to handle an overheating concern of high-power-density electronics. Herein, we constructed a snail shell-like thermal conductive framework to facilitate vertical heat conduction in TIMs. With inspiration from spirally growing calcium carbonate platelets of snail shells, a facile double-microrod-assisted curliness method was developed to spirally coil boron nitride nanosheet (BNNS)/aramid nanofiber (ANF) laminates where interconnected BNNSs lie along the horizontal plane. Thus, vertical alignment of BNNSs in the resultant TIM was achieved, exhibiting a through-plane TC enhancement of ∼100% compared to the counterpart with randomly distributed BNNSs at the same BNNS addition (50 wt %). The Foygel's nonlinear model revealed that this unique snail shell-like BNNS framework reduced interfacial thermal resistance by 4 orders of magnitude. Our TIM showed superior interfacial thermal dissipation efficiency, leading to a temperature reduction of 42.6 °C for the LED chip compared to the aforementioned counterpart. Our work paves a valuable way for fabricating high-performance TIMs to ensure reliable operation of electrical devices.

Local structure engineering of Ba1-xKxLa2Y2(SiO4)2O1-α: Eu2+ green phosphors for violet-light-excitable full-spectrum lighting

To achieve comfortable and healthy full-spectrum lighting, the development of efficient and stable violet-light-excitable phosphors is urgently required. Herein, we report a new type of green-emitting phosphor, Ba1-xKxLa2Y2(SiO4)2O1-α: Eu2+ (x=0–1). Interestingly, K+-alloying leads to continuous redshift of green emission from 500 nm to 517 nm accompanied with reduced full width at half maximum (FWHM) from 72 nm to 63 nm and enhanced excitation intensity in the violet spectral region. Rietveld refinements and spectral analysis evidence that K+-addition enhances the distortion of [M(Ⅰ)O9] and [M(Ⅱ)O7] (M(Ⅰ/Ⅱ) = Ba, La, Y, K) polyhedron and strengthens crystal field around Eu2+, which is responsible for the observed photoluminescence (PL) phenomenon. Finally, we design a full-spectrum white light emitting diode (WLED) with an ultra-high color rendering index (CRI, Ra) of 97.4 by coupling the as-prepared green-emitting phosphor (Ba0.7K0.3La2Y2(SiO4)2O1-α: Eu2+) and commercial blue/red phosphors with a violet LED chip, which demonstrates significant potential for application in healthy solid-state lighting.